White adipose tissue (WAT) is one of the most abundant tissues in mammals, exhibiting numerous complex functions. The primary purpose of WAT is to store excess energy in the form of fat for future use by other cells of the organism during periods of energy deprivation. In order to do this, white adipocytes acquire the expression of specific enzymes during their differentiation, which enable both the accumulation and mobilization of fat. Fat accumulation is achieved by de novo synthesis of fatty acids (lipogenesis) as well as fatty acid uptake, while fat mobilization is accomplished during lipolysis. Both processes are regulated by various hormones including insulin and catecholamines. In addition, WAT secrete various factors, known as adipokines, which can act locally or distally on other tissues. These adipokines, which include leptin, adiponectin, RBP4, and others, are involved in the regulation of whole body energy homeostasis. In mammals, WAT is distributed throughout the body in two main depots, located subcutaneously and intra-abdominally. In obesity, intra-abdominal fat accumulation is strongly associated with the development of related diseases, including type 2 diabetes, while accumulation of subcutaneous fat exhibits no correlation. This phenomenon is the result of differences in anatomical location and developmental intrinsic properties of subcutaneous and intra-abdominal white adipose depots. In this chapter, we discuss how the developmental origins of fat may play a role in the heterogeneity in WAT distribution and function and the impact of fat distribution on obesity-related diseases.